Two problems related to transmission not go into gear have been reported for the 2018 Ford Mustang. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2018 Ford Mustang based on all problems reported for the 2018 Mustang.
Vehicle experiences random non repeatable periods of hard shifting, refusal to go into gear, grinding gears, jerkiness and what feels occasionally like transmission slips. When it occurs it mostly happens under heavy acceleration such as trying to get up to speed on an on ramp or trying to get to highway speeds but not always. Recently while traveling in a 45mph zone I attempted to shift into 3rd gear. Clutch was fully depressed and noticable gear grinding happened and an immediate second attempt resulted in same result. Had to shift to 4th causing vehicle to be in unacceptable gear range for current speed. Service appointment at dealership made June 10th 2020. Issue has happened several times previously but seems to be getting worse. Last known incident happened June 11 2020 at approximately 3:30 pm est one day after making appointment with dealership.
When getting up to speed on an on ramp or passing on a two la e road, when shifting into third gear, the transmission will not go into gear. I've had this happen twice, once my daughter was with me on a two lane road, going from second to third while passing, the car will not allow it. People have noted this many places while running out second gear and shifting into third in multi situations. This is a hazard and it is known due to the shifter not being direct and using a remote linkage. An aftermarket bracket and shifter will fix this issue, however this vehicle should operate safely without purchasing aftermarket equipment. Simple look up missed shifts with mt-82 Mustang transmission. You will see many with the same issue and aftermarket parts to fix this safety hazard.